1. Field of the Invention
The invention relates to a chip package structure and a manufacturing method thereof. More particularly, the invention relates to a package carrier and a manufacturing method thereof.
2. Description of Related Art
The purpose of a chip package is to protect a bare chip, lower the chip contact density, and provide the chip with good heat dissipation. A leadframe serving as a carrier of a chip is frequently employed in a conventional wire bonding technique. As contact density on a chip gradually increases, the leadframe which is unable to satisfy current demands on the high contact density is replaced by a package substrate which can achieve favorable contact density. Besides, the chip is packaged onto the package substrate by conductive media, such as metal wires or bumps.
Regarding current and common light emitting diode (LED) package structures, an LED chip is packaged before use. The LED chip emits light and generates a large amount of thermal energy simultaneously. If the thermal energy generated by the LED chip is unable to quickly dissipate and amasses within the LED package structure, the temperature of the LED package structure will be raised continuously. Therefore, the LED chip may have decayed illumination and a shorter lifetime, and if serious, may even have permanent damage due to overheating.
Since the thermal expansion coefficients of a LED chip and a package carrier are mismatched, the generated thermal stress and warpage are more and more critical so that the reliability of the LED package structure is lowered. Thus, besides enhancing the light extraction efficiency, the current package technology focuses on decreasing the thermal stress of the package structure to increase the lifetime and the reliability.